I am working on program that remove duplicates from an array I am using three functions here: one to take the input such as the size and the number, second function to remove duplicates and return the number without duplicates and the third function just a report show the size and the new number but I am having problem I don't know in what step I think in report or phillip erreur:
In function ‘int main()’: invalid conversion from ‘int*’ to ‘int’,initializing argument 1 of ‘void report(int, int)’
#include <iostream>
using namespace std;
const int size = 100;
void phillip(int[], int & );
/* Preconditions: Array of base type in declared and int varuable declared
postconditions: the array is filled with values supllied by the user at
the keybord. the user is assked how many values they want - this value is
given to the second argument.
*/
int remdubs(int[], int noel);
/* Preconditions: An array of basetype int that has noel values.
postconditions: The number of unique elemts in the array is returned. The function removes all dubplicates inside the array.
*/
void report(int s, int d);
int main()
{
int ruby[size];
int numele, numuniq;
phillip(ruby, numele);
numuniq = remdubs(ruby, numele);
report(ruby, numuniq);
return 0;
}
void phillip(int[], int& )
{
int s;
cout << "\nHow many values you want? ";
cin >> s;
cout << "\nPlease input 10 integers, hitting return after each one \n";
for (int i = 0; i < s; i++)
{
int num;
cin >> num;
}
}
int rembups(int sapphire[], int noel)
{
for (int i = 0; i < noel; i++)
{
for (int j = i + 1; j < noel; j++)
{
if (sapphire[i] == sapphire[j])
{
for (int k = j; k < noel; k++)
sapphire[k] = sapphire[k + 1];
noel--;
j--;
}
}
}
return noel;
}
void report(int s, int d)
{
cout << "\nYou entered " << s << "distinct numbers: " << d;
}
Can't explain it better than your error:
void report (int s, int d);
this function asks for two integer values, you're passing an array to it which, with decayed functionalities, will behave like an integer pointer
int ruby[size];
report (ruby, numuniq);
I'm unsure on the behavior of your program but you should rather do something like
report(ruby[0], numuniq);
that is: access the element of the array and feed it to the function
The error is in the function report, it asks for two integer and you are passing an array and an integer instead
and again i don't think you need 2 parameters in the function report one would solve your purpose
void report(int d)
{
cout << "\nYou entered <<d<<" distinct numbers";
}
that would solve your error but i don't think you would get your desired output
Few problems with the code:
Report function should be expecting an array of integers rather than single integer
Try using human readable variable or function names
remdubs was renamed to rempubs in function definition
phillip function definition didn't have params defined properly
You have const int size but do not use it
remdups has a bug somewhere. I will leave that out as I am trying to fix other issues here.
There are better ways of finding duplicates than remdups. Please look at some other solutions.
I have fixed your code and provided it here on ideone
Related
This is my first C++ class and I'm not really sure how to proceed in my homework, as understanding arrays has been fairly difficult for me. I've successfully completed the 1st task, but got stuck understanding the 2nd and don't really know how to start it.
The tasks are:
Define a function named harmonicNum() that finds and returns the nth harmonic number using an iteration statement where n is a positive int-typed argument provided by the caller.
Given a valid array index i, define a function named fillHarmonic() that iteratively calls harmonicNum() to initialize the ith element of an array parameter wit the i+1th number of the harmonic series. I must define this function to work on a one-dimensional array of any size.
This is the code that I have so far:
#include <iostream>
#include <cmath>
using namespace std;
double harmonicNum(int n);
int n;
int main()
{
do
{
cout << "Please input a positive integer: " << endl;
cin >> n;
} while (n < 0);
cout << harmonicNum(n) << endl;
return 0;
}
double harmonicNum(n)
{
double harmonic = 0.00
for (int i = 1; i <= n; i++)
{
harmonic = harmonic + 1.00 / i;
}
return harmonic;
}
Something like this?
Method definition:
void fillHarmonic(double &i_elem, int i){
i_elem = harmonicNum(i+1);
}
Call without error checking:
double arr [5];
//TODO init values
for(int i = 0; i < (sizeof(arr)/sizeof(double)); i++ ){
fillHarmonic(arr[i], i);
}
I'm new to C++ and for now there is one thing I would want to make clear. As I'm going through the tutorial,there is this program that stores user's input into an array and gives a sum of all numbers when the user exits the program:
//PROTOTYPE DECLARATION:
int readArray(int integerArray[], int maxNumElements);
int sumArray(int integerArray[], int numElements);
void displayArray(int integerArray[], int numElements);
int main(int nNumberofArgs, char* pszArgs[])
{
cout << "This program sums values entered\n";
cout << "Terminate the loop by entering a negative number" << endl;
//store the numbers from the user into a local array
int inputValues [128];
int numberOfValues = readArray(inputValues, 128);
//output the values and the sum of the values
displayArray(inputValues, numberOfValues);
cout << "The sum is " << sumArray(inputValues, numberOfValues) << endl;
return 0;
}
int readArray(int integerArray[], int maxNumElements)
{
int numberOfValues;
for(numberOfValues = 0; numberOfValues < maxNumElements; numberOfValues++)
{
//fetch another number
int integerValue;
cout << "Enter next number: ";
cin >> integerValue;
if (integerValue < 0)
{
break;
}
//otherwise store the number into the storage array
integerArray[numberOfValues] = integerValue;
}
//return the number of elements read
return numberOfValues;
}
//displayArray - display the members of an array:
void displayArray(int integerArray[], int numElements)
{
cout << "The value of the array is:" << endl;
for(int i = 0; i < numElements; i++)
{
cout << i << ":" << integerArray[i] << endl;
}
cout << endl;
}
//sumArray
int sumArray(int integerArray[], int numElements)
{
int accumulator = 0;
for(int i = 0; i < numElements; i++)
{
accumulator += integerArray[i];
}
return accumulator;
}
My questions are:
Is it neccessary to declare local variables in each function (e.g. int inputValues [128];)?
Would it be correct to store the input into the arguments that were declared in the function prototype? For example, can we just store everything into integerArray[] instead of creating a storage array integerValue ?
This may look obvious but I want to understand this to avoid making mistakes in the future.
inputValues is necessary if you want to pass an array to the function.
int inputValues [128];
int numberOfValues = readArray(inputValues, 128); //passing array to function
Either way you do it is fine. So what you have is not wrong.
As noted in the comments you could also pass inputValues by reference. Which you could declare the prototype of function like this.
int readArray(int (&integerArray)[128]);
Any changes you make to the array you passed by reference will be updated when the function returns to main because you are not operating on a copy of the array anymore.
Edit:
As #Kevin pointed out, you can use a template function to get the size of the array at compile time.
template<size_t N> int readArray(int (&integerArray)[N]);
There are a lot of understanding gaps in this question.
The function parameter lists will convert their input:
If the type is "array of T" or "array of unknown bound of T", it is replaced by the type "pointer to T"
Using the implicit array to pointer assignment:
Constructs a pointer to the first element of an array.
These two together hopefully help you to see that when you declare a function like: int readArray(int integerArray[], int maxNumElements), integerArray is really just a pointer to the first element of it's first argument. You call readArray(inputValues, 128) so the parameter integerArray is equivalent to &intputArray[0].
It is not necessary and you can use global variables instead but that is bad choice in terms security and visibility etc. This program can be done few different ways but I guess what you need to learn first is difference between local and global scope, pointer/array.
In the program, memory is allocated for
int inputValues[128]; //memory allocation
Then address of that location is passed here.
int numberOfValues = readArray(inputValues, 128);
It is much more efficient this way. But it will start make more sense once you get more experience with pointer and arrays.
I wrote a basic linear search C++ code. Whenever I run this, the result I get is always the opposite of the expected result.
For instance, I want to search 4. In an array where it is present, it will say the number is not found, but upon searching an absent element, it will say the element is found at position 0.
Even after an hour or so of constantly looking at the code I have not found any solution.
#include <iostream>
using namespace std;
//scanning program
int linearsearch (int A[] , int z, int n, int srchElement) {
for (int z = 0; z < n; z++) {
if (A[z] == srchElement) {
return z;
}
}
return -1;
}
//main program
int main () {
int i, n, A[1000], z;
//asking for size of array
cout << "give size of the array needed to be scanned: ";
cin >> n;
cout << endl;
if (n > 999) {
cout << "invalid value";
return -1;
}
//making sure of the size of the array
cout << "enter " << n << " integers: ";
//asking for the array
for (i = 0; i < n; i++) {
cin >> A[i];
}
int srchElement, index;
do {
cout << endl << "enter element to search (-1 to exit ): ";
//srchElement is defined here
cin >> srchElement;
if (srchElement == -1) break;
index = linearsearch(A, n, srchElement, z);
//calling thscanning function
if (index == -1) {
cout << srchElement << " not present" << endl;
}
//outputting the results of the scan
else {
cout << srchElement << " present " << index << endl;
}
} while (true);
return 0;
}
Your parameters to linearsearch are not in the correct order - you are passing n into the unused z parameter. With your current function you should call it like:
index=linearsearch(A, 8675309, n, srchElement);
I recommend you get rid of z as a parameter, then you won't need to pass a value to it.
Also please note: Spaces and indentation do not make your program run slower, but they do make it a lot easier to read.
The order of arguments in the function definition is not the same as in the function call.
It should be like (Line no 4):
int linearsearch (int A[] , int n, int srchElement, int z)
This is your search function correctly formatted:
int linearsearch (int A[] , int z, int n, int srchElement)
{
for (int z = 0; z < n; z++)
{
if(A[z] == srchElement)
{return z;}
}
return -1;
}
and here is how you call it:
index=linearsearch(A, n, srchElement, z);
You pass a value z in with the call. It is unitialised and does nothing, in main() or in the function.
You pass the arguments into the function in the wrong order. You are:
passing n (from main()) into the unused z value
searching for the uninitialised z (from main())
passing in the element you are looking for as n (array size). (This will quite likely result in out of bounds error, e.g. if searching for -1)
Try this:
int linearsearch (int A[], int n, int srchElement)
{
for (int z = 0; z < n; z++)
{
if(A[z] == srchElement)
{return z;}
}
return -1;
}
and here is how you call it:
index=linearsearch(A, n, srchElement);
You immediate problem: as The Dark spotted, this call:
index=linearsearch(A, n, srchElement, z);
doesn't match the declaration
int linearsearch (int A[] , int z, int n, int srchElement)
Function arguments in C++ are positional: just because the last call argument and the second declaration parameter are both called z doesn't mean anything.
Now, there are several local issues of style:
this kind of function is risky in the first place
int linearsearch (int[],int,int,int)
because it relies on you remembering the correct order for the last three integer parameters. If you must do this, you should be extra careful to give them all distinctive names, be very clear about which is which, and keep the order consistent across families of functions.
It's better, where possible, to help the compiler help you out, by either giving the arguments distinct types (or enumerations, or whatever), or grouping them into a structure.
For example, using a std::vector<int> instead of your array effectively groups int A[] and int n together in an object, so they can't get out of sync and n can't get confused with the other integers floating around
You shouldn't be passing z in the first place. You immediately hide it with a local int z in the loop, so it can't be doing anything. Remove it from both the declaration and the call. This simplification is sufficient to fix your bug.
Your secondary problem is that the code is ugly. It's poorly formatted and hard to read, and and that makes it more difficult to spot mistakes. Try to make your code simple and readable: there's less opportunity for things to go wrong, and its easier to see the problems when they occur.
Your tertiary problem is that the code is bad. Most of this can be done using standard library facilities (making your code simpler), which are themselves well-tested and generally have carefully-designed interfaces. Use them first, and replace if necessary.
#include <iostream>
using namespace std;
const int MAX = 1000;
int ArrMix[MAX];
int *ptrArrPos[MAX];
int *ptrArrNeg[MAX];
int PosCounter = 0;
int NegCounter = 0;
int r;
void accept(int ArrMix[MAX])
{
cout<<"Enter the number of elements in your array: ";
cin>>r;
for (int i = 0; i < r; i++)
{
cout<<"Enter value:";
cin>>ArrMix[i];
}
}
void process(int &i)
{
if(ArrMix[i] >= 0)
{
ptrArrPos[PosCounter] = &ArrMix[i];
PosCounter++;
}
else
{
ptrArrNeg[NegCounter] = &ArrMix[i];
NegCounter++;
}
}
void display(int &i)
{
cout<<"Your passed array is: " << endl;
cout<<ArrMix[i] << endl;
cout <<"Total number of positive integers is: "<<PosCounter<<endl;
cout<<"Your positive array is: "<<endl;
for (int i = 0; i < PosCounter; i++)
{
cout << *ptrArrPos[i] << endl;
}
cout<<endl;
cout <<"Total number of Negative integers is: "<<NegCounter<<endl;
cout<<"Your negative array is: "<<endl;
for (int i = 0; i < NegCounter; i++)
{
cout << *ptrArrNeg[i] << endl;
}
}
int main ()
{
int *i;
int a = &i;
accept(&ArrMix[MAX]);
process(a);
display(a);
system("pause>0");
}
The code you see above is a program use to create a user-defined array list of numbers. It should accept numbers from the user, display the passed array, positive numbers array and its negative numbers array. it should evaluate items, meaning separating negatives #s from positive numbers then creating an array for each. next is to use a counter to identify how many positive #s and negative #s are in each array.
I am having problems in passing the array from one function to another using pointers and calling it in the main function. so please help me?
The expression &ArrMix[MAX] returns a pointer to the integer at index MAX in the array. This index is one beyond the array, meaning you pass a pointer to beyond the array to the function which will then happily write to that memory.
Passing an array is as simple as passing any other argument:
accept(ArrMix);
You also have a problem here:
int *i;
int a = &i;
You declare i to be a pointer to an int. Then you use &i which returns the address of the variable i, in other words a pointer to a pointer to an int, and try to assign this double-pointer to a normal int variable.
It seems to me that you might want to return the number of entries is in the array from the access function, and then loop over the entries the user entered in the array and call process for each value. And then in display instead of taking the ArrMix index it should take the size and loop over that to display the ArrMix array.
I know my code isnt finished yet im not asking for it to be done. It's supposed to input food eaten by 3 monkeys over a week and other stuff. But I've hit a snag. It gives me an error(Error: no operator "<<" matches these operands) when i put the cin in the poundsEaten function. Am I not passing the array right is that why it isnt working? Thanks for any help
#include <iomanip>
#include <iostream>
using namespace std;
//Global Constants
const int NUM_MONKEYS = 3;
const int DAYS = 7;
//Prototypes
void poundsEaten(const double[][DAYS],int, int);
void averageEaten();
void least();
void most();
int main()
{
//const int NUM_MONKEYS = 3;
//const int DAYS = 7;
double foodEaten[NUM_MONKEYS][DAYS]; //Array with 3 rows, 7 columns
poundsEaten(foodEaten, NUM_MONKEYS, DAYS);
system("pause");
return 0;
}
void poundsEaten(const double array[][DAYS], int rows, int cols)
{
for(int index = 0; index < rows; index++)
{
for(int count = 0; count < DAYS; count++)
{
cout << "Pounds of food eaten on day " << (index + 1);
cout << " by monkey " << (count + 1);
cin >> array[index][count];
// Here is where i get the error
}
}
}
You've declared array as containing const doubles. They're constant, so you can't write to them as you are trying to do with cin >> array[index][count];. Just change the parameter declaration to:
double array[][DAYS]
Perhaps you should think about when and why you should declare a variable as const.
As an aside to avoid later confusion, it's worth mentioning here that there's no such thing as array type parameters. The above parameter is actually transformed to:
double (*array)[DAYS]
However, your code is written appropriately to work with this (you passed the number of rows to the function).
you declare:
const double array[][DAYS],
however, inside poundsEaten function, you are asking user to input information to fill in the array, which means the array is not const, therefore, error. Remove the const qualifier from the parameter such that the array can be changed by user input.
void poundsEaten(double array[][DAYS], int rows, int cols)
BTW: don't use array as variable name for an array, use some other names for good practice.
Meanwhile,cols is not used inside your poundsEaten function.